NYPD: Suspect in stabbing found dead

September 30, 2009 12:14:30 PM PDT

NEW YORK --

A man suspected of killing someone he bumped into on a sidewalk outside New York City's main post office has been found dead in Philadelphia, police said Wednesday. The man was found in the bathroom of an ex-girlfriend's apartment; the death is being investigated as a possible suicide, according to police in New York. The medical examiner's office in Philadelphia will determine the cause of death.

The normally bustling James A. Farley Post Office is across the street from Madison Square Garden and Pennsylvania Station, and just blocks from the Empire State Building.

The security video showed the pedestrians walking toward each other and bumping shoulders on Sunday. Each kept walking for a moment, but then they turned, exchanged words and moved toward each other.

The victim, 20-year-old Christopher Gutierrez of Manhattan, assumed a fight-like stance, and the suspect made jabbing motions, stabbing him. Gutierrez was stabbed three times, then the dying victim slumped to the post office steps. The suspect picked up something on the ground, possibly his cell phone, then walked away.

A German tourist photographed the suspect, who was identified Tuesday by Police Commissioner Raymond Kelly as Sir'mone McCaulla, 28. He was identified by three calls to the city's tips hot line. He had three prior arrests for minor offenses and served as a soldier in the Army reserve in Kuwait, Kelly said.

Philadelphia officials notified police in New York on Tuesday night that the suspect had been found dead.

The Daily News of New York reported McCaulla e-mailed a rambling suicide note to his mother, saying he didn't mean to kill Gutierrez, claimed he was acting in self defense because he had been jumped by "white guys" before, and asked her to look over his daughter.